Question to the Department of Health and Social Care:

To ask the Secretary of State for Health and Social Care, what expert analysis he has received on the effect of a high viral load of covid-19 circulation on covid-19 transmission among people who have (a) received a covid-19 vaccine and (b) people who have not received a covid-19 vaccine.

There is evidence from a range of studies that COVID-19 vaccines are effective at preventing infection with the COVID-19 virus. Public Health England (PHE) participated in two studies, which looked at vaccine effectiveness against COVID-19 infection in different populations, including the impact of vaccination on infection, viral load and transmission.

The studies have been published in The Lancet at the following link:

https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(21)00354-6/fulltext

https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)00790-X/fulltext

PHE also studied the effect of vaccination on household transmission of COVID-19 in England. The findings showed that individuals who become infected despite vaccination have lower viral load and are less likely to transmit. This study is available at the following link:

https://www.nejm.org/doi/full/10.1056/NEJMc2107717